Air cooler



FIG. 1 is a perspective view of an air cooler according to our design;

FIG. 2 is a front view of the air cooler;

FIG. 3 is a rear view of the air cooler;

FIG. 4 is a right view of the air cooler;

FIG. 5 is a left view of the air cooler;

FIG. 6 is a top view of the air cooler; and,

FIG. 7 is a bottom view of the air cooler.

The broken lines in the drawings illustrate portions of the air cooler which form no part of the claimed design. 

CLAIM The ornamental design for an air cooler, as shown and described. 